Overview

This example shows how to configure Common Pervasive Gateway for IPv4 when using the Cisco APIC.

Two ACI fabrics can be
configured with an IPv4 common gateway on a per bridge domain basis. Doing so
enables moving one or more virtual machine (VM) or conventional hosts across
the fabrics while the host retains its IP address. VM host moves across fabrics
can be done automatically by the VM hypervisor. The ACI fabrics can be
co-located, or provisioned across multiple sites. The Layer 2 connection
between the ACI fabrics can be a local link, or can be across a bridged
network. The following figure illustrates the basic common pervasive gateway
topology.

Note

Depending upon the topology used to interconnect two Cisco ACI fabrics, it is required that the interconnecting devices filter
out the traffic source with the Virtual MAC address of the gateway switch virtual interface (SVI).

Configuring Common
Pervasive Gateway Using the GUI

Before you begin

The tenant and VRF are created.

The bridge
domain virtual MAC address and the subnet virtual IP address must be the same
across all ACI fabrics for that bridge domain. Multiple bridge domains can be
configured to communicate across connected ACI fabrics. The virtual MAC address
and the virtual IP address can be shared across bridge domains.

The Bridge
domain that is configured to communicate across ACI fabrics must be in
flood mode

Only one EPG
from a bridge domain (If the BD has multiple EPGs) should be configured on a
border Leaf on the port which is connected to the second Fabric.

Do not connect
hosts directly to an inter-connected Layer 2 network that enables a pervasive
common gateway among the two ACI fabrics.

In the Make this IP address primary field, check the check box to specify this IP address for DHCP relay.

Checking this check box affects DHCP relay only.

Click Ok, and click Finish.

Expand Subnets again, and in the Create Subnets dialog box, to create the Physical IP address in the Gateway IP field, use the same subnet which is configured as the Virtual IP address.

Note

The Physical IP address must be unique across the ACI fabric.

Step 5

Complete the appropriate steps and click Finish to complete.

Step 6

Double click the Bridge Domain that you just created in the Work pane, and perform the following action:

In the L3 Configurations tab, click the Virtual MAC Address field, and change not-applicable to the appropriate value. Click Submit.

Note

The default BD MAC address values are the same for all ACI fabrics; this configuration requires the bridge domain MAC values
to be unique for each ACI fabric.

Confirm that the bridge domain MAC (pmac) values for each fabric are unique.

Step 7

To create an L2Out EPG to extend the BD to another fabric, in the Navigation pane, right-click External Bridged Networks and open the Create Bridged Outside dialog box, and perform the following actions: